The first day of my last period was November 1. On November 9 I went out for a friend's birthday, we had too much to drink and ended up having unprotected sex. The next morning I went out and took Plan B. I track my period on my phone using an app called Clue. That morning, the 10, I saw that I had entered my fertile window and was expected to ovulate on the 14th. Then yesterday, the 19th, I noticed that I was spotting it was light pink and very minimal but was not the same as my normal pre-period spotting. Today it is darker brown but still very minimal. I know that Plan B is very effective when taken within the first 72 hours but I've read that it is less effective on women who have BMI over 25 (mine is about 33). So I guess my question is: is the spotting I am experiencing a side effect of the Plan B or is it implantation bleeding? Any feedback is welcome.
Thanks!